A veteran defense attorney running an independent campaign for Baltimore state's attorney was dealt a significant setback Friday when elections officials determined that he did not collect enough signatures to appear on the November ballot.

Russell A. Neverdon Sr. fell more than 1,000 signatures short of the 4,160 needed to challenge Democrat Marilyn J. Mosby, a city official said.

Neverdon said he will appeal the decision to Baltimore Circuit Court and, failing that, would consider running a write-in campaign for the job.

"This fight has not ended by any stretch of the imagination," Neverdon said outside the offices of the Baltimore City Board of Elections. "It is just beginning."

Mosby, who upset incumbent State's Attorney Gregg L. Bernstein in the June 24 primary, didn't see it that way. In a statement Friday, she declared victory, arguing that the Democratic process had "played itself out."

No Republican is running.

"I look forward to a successful transition into one of Baltimore's most important elected positions," Mosby said. "I will be ready on day one to pursue the violent repeat offenders that are destroying our neighborhoods."

Neverdon said his campaign closely reviewed the 5,686 signatures his campaign had collected before submitting them to the Board of Elections last week and argued that far more signatures should have counted.

But Armstead B.C. Jones Sr., director of the city elections board, said nearly 500 of Neverdon's signatures belonged to people who are not registered to vote in Baltimore. Another 300 did not have dates affixed. Both are required for the signature to be valid.

Jones said his review, which he said was conducted twice to ensure accuracy, took about one week to complete and that he is confident in the outcome. Jones said successful ballot-access campaigns often submit double the number of signatures required to give candidates a cushion.

Maryland law requires that signatures exactly match names as they appear in state voter registration rolls. The standard prompted groups looking to overturn state laws on same-sex marriage and redistricting in 2012 to use new technology that allowed voters to check their names in the rolls.

Neverdon said his campaign created its own verification system based on the voter file provided by the city elections board.

State law allows Neverdon to appeal to Circuit Court, but time is tight. Jones said his office must complete the first draft of the general election ballot by Aug. 22.

It's not clear how long a judicial review of the signatures would take.

Neverdon supporters carried the signatures to the elections office in a safe, which they said was necessary after some petitions were burned during a fire in May at his campaign headquarters. The office on North Avenue was destroyed by what Neverdon described as a "mysterious" fire.

Mosby has enjoyed a fundraising lead, has the support of a majority of the City Council and is working with noted fundraiser Colleen Martin-Lauer.